Moving lightweight Java forward is a real business for virtualization vendor VMware's SpringSource division, today unveiling Spring 3.0 -- an effort that bring a new expression language and more optimization to its lightweight Java framework.

Since its creation, Spring has grown in popularity as an open source Java framework -- today counting more than 3 million users -- by promising to enable enterprise Java applications with less overhead.

"The introduction of the expression language and enhancements to Spring MVC will allow users to make a noticeable reduction in the amount of code and configuration they have in their applications," Rod Johnson, Spring's founder and creator, told InternetNews.com. "Spring 3.0 essentially continues the work of Spring 2.5 and earlier versions to make applications simpler. Fundamentally, we are adding sophistication in the framework with the aim of making applications simpler."

The new Spring expression language works with Java annotations so that developers can write and point to their configurations without the need to write separate XML files. Johnson noted that in his view, the role of the framework should be to help enable applications developers focus on business logic. Johnson first previewed Spring 3.0 at the JavaOne conference earlier this year.

The Spring 3.0 release also marks a Java milestone for users in that the framework now requires JavaEE 5.0 or higher. JavaEE 5.0 has been available since 2006, though previous versions of Spring did not require it and were able to work on older versions of JavaEE (also known as J2EE).

"There is a general updating of Spring to take advantage of newer language features in newer versions of Java," Johnson said. "Previous versions of Spring had some additional language support but were just layered on top of the original Spring APIs. Now what we've done is make Spring require Java 5 or above. This has enabled us to go through the framework internally and rewrite internal APIs to take advantage of new language features."

Johnson added that if developers are unable to update their version of Java, they can stay on Spring 2.5. Overall, though, Johnson said there is a high degree of backward compatibility between applications written for earlier versions of Spring and the new Spring 3.0 release.

Spring tc Server Developer Edition

Alongside the Spring 3.0 release, SpringSource is rolling out a new developer-focused version of its Apache Tomcat tc server. The tc Server debuted in April as a SpringSource effort to provide a commercially supported version of the popular open source Apache Tomcat Java application server.

Shaun Connolly, vice president of product management for SpringSource, explained to InternetNews.com that one of the key additions to the release -- dubbed tc Server developer edition -- is the inclusion of what's known as Spring Insight.

"With Spring Insight, developers are able to get performance insight into their applications with histograms and response time charts and they're able to analyze performance at every level of the Spring application," Connolly said. "The intent is aimed at Agile developers and QA teams so they can get a deeper level of insight into Spring applications as they are being developed."

Spring Insight owes part of its development to an acquisition that SpringSource completed prior to being purchased by VMware. SpringSource bought open source systems monitoring vendor Hyperic in May, and Connolly noted that a Hyperic engineer had been a key contributor to the new Spring Insight tool.

Overall, the goal with the tc Server developer edition is to help bridge the gap between developers and operations. The tc Server release integrates with the Spring Tool Suite (STS), which is also getting an incremental update to support Spring 3.0.

"With easy integration into the tool suite, you can jump straight from the diagnostics in the tc Server to the actual code that may have may been causing the problem, right in the SpringSource tool suite," Johnson said.